U.S. patent number 7,535,680 [Application Number 11/169,003] was granted by the patent office on 2009-05-19 for micro-actuator with integrated trace and bonding pad support.
This patent grant is currently assigned to SAE Magnetics (H.K.) Ltd.. Invention is credited to Wei Ma, MingGao Yao.
United States Patent |
7,535,680 |
Yao , et al. |
May 19, 2009 |
Micro-actuator with integrated trace and bonding pad support
Abstract
A micro-actuator for a head gimbal assembly includes a frame, a
first set of bonding pads provided to one end of the frame, a
second set of bonding pads provided to an opposing end of the
frame, and a trace integrated to the frame. The trace interconnects
the first set of bonding pads and the second set of bonding
pads.
Inventors: |
Yao; MingGao (DongGuan,
CN), Ma; Wei (DongGuan, CN) |
Assignee: |
SAE Magnetics (H.K.) Ltd. (Hong
Kong, CN)
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Family
ID: |
37589204 |
Appl.
No.: |
11/169,003 |
Filed: |
June 29, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070002500 A1 |
Jan 4, 2007 |
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Current U.S.
Class: |
360/294.4 |
Current CPC
Class: |
G11B
5/5556 (20130101) |
Current International
Class: |
G11B
5/56 (20060101); G11B 21/20 (20060101) |
Field of
Search: |
;360/294.4 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2002-74871 |
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Mar 2002 |
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JP |
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2002-133803 |
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May 2002 |
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JP |
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Other References
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other .
U.S. Appl. No. 11/050,823, filed Jan. 2005, Yao et al. cited by
other .
U.S. Appl. No. 11/080,657, filed Mar. 2005, Zhu et al. cited by
other .
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other .
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U.S. Appl. No. 11/265,385, filed Nov. 2005, Yao et al. cited by
other .
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other .
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.
U.S. Appl. No. 11/300,339, filed Dec. 2005, Yao et al. cited by
other .
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other .
U.S. Appl. No. 11/385,698, filed Mar. 2006, Yao et al. cited by
other .
U.S. Appl. No. 11/319,577, filed Dec. 2005, Yao et al. cited by
other .
U.S. Appl. No. 11/353,018, filed Feb. 2006, Yao. cited by other
.
U.S. Appl. No. 11/273,075, filed Nov. 2005, Yao. cited by other
.
U.S. Appl. No. 11/319,580, filed Dec. 2005, Yao et al. cited by
other .
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.
U.S. Appl. No. 11/414,546, filed May 2006, Yao et al. cited by
other .
U.S. Appl. No. 11/440,354, filed May 2006, Li. cited by
other.
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Primary Examiner: Klimowicz; William J
Attorney, Agent or Firm: Nixon & Vanderhye P.C.
Claims
What is claimed is:
1. A micro-actuator for a head gimbal assembly, comprising: a
frame; a first set of bonding pads provided to one end of the frame
and a second set of bonding pads provided to an opposing end of the
frame; and a trace integrated to the frame, the trace
interconnecting the first set of bonding pads and the second set of
bonding pads, wherein the trace is substantially planar with
respect to a single surface of the frame.
2. The micro-actuator according to claim 1, wherein the frame
includes a bonding pad support integrated to the frame, the bonding
pad support supporting one of the first set of bonding pads and the
second set of bonding pads.
3. The micro-actuator according to claim 1, wherein the frame
includes a bonding pad support integrated to the frame, the bonding
pad support having at least one opening that supports and exposes
one of the first set of bonding pads and the second set of bonding
pads.
4. A micro-actuator for a head gimbal assembly, comprising: a
bottom support adapted to be connected to a suspension of the head
gimbal assembly, the bottom support including suspension bonding
pads adapted to be electrically bonded with respective pads
provided on the suspension; a top support adapted to support a
slider of the head gimbal assembly; a pair of side arms that
interconnect the bottom support and the top support; a PZT element
mounted to each of the side arms, each PZT element being excitable
to cause selective movement of the side arms which causes movement
of the top support to cause movement of the slider; and a bonding
pad support integrated to and extending from the top support, the
bonding pad support including slider bonding pads adapted to be
electrically bonded with respective pads provided on the slider,
wherein the suspension bonding pads are electrically connected to
the slider bonding pads through a trace that is integrated to the
bottom support, the top support and the bonding pad support and
supported only by the bottom support, the top support and the
bonding pad support.
5. The micro-actuator according to claim 4, wherein the trace
includes opposing trace lines having intermediate portions that
curve inwardly towards one another.
6. The micro-actuator according to claim 4, wherein the trace
includes opposing trace lines having intermediate portions that
curve outwardly away from one another.
7. The micro-actuator according to claim 4, wherein the trace
includes opposing trace lines having end portions that curve
inwardly towards one another.
8. The micro-actuator according to claim 4, wherein the trace
includes opposing trace lines that are substantially parallel with
one another.
9. The micro-actuator according to claim 4, wherein the trace is
integrated into a front surface of the bottom support, the top
support, and the bonding pad support that faces towards the
slider.
10. The micro-actuator according to claim 4, wherein the trace is
integrated into a back surface of the bottom support, the top
support, and the bonding pad support that faces away from the
slider.
11. The micro-actuator according to claim 10, wherein the bonding
pad support includes an opening that exposes the slider bonding
pads so that the slider bonding pads can be electrically bonded
with respective pads provided on the slider.
12. The micro-actuator according to claim 4, further comprising an
extension integrated to and extending from the bottom support, the
extension including suspension bonding pads adapted to be
electrically bonded with respective pads provided on the
suspension.
13. The micro-actuator according to claim 12, wherein the
suspension bonding pads are electrically connected to the slider
bonding pads through a trace that is integrated into the bottom
support, the top support, the bonding pad support, and the
extension.
14. The micro-actuator according to claim 13, wherein the trace
includes opposing trace lines having intermediate portions that
curve inwardly towards one another.
15. The micro-actuator according to claim 13, wherein the trace is
integrated into a front surface of the bottom support, the top
support, the bonding pad support, and the extension that faces
towards the slider.
16. The micro-actuator according to claim 13, wherein the trace is
integrated into a back surface of the bottom support, the top
support, the bonding pad support, and the extension that faces away
from the slider.
17. The micro-actuator according to claim 16, wherein the bonding
pad support includes an opening that exposes the slider bonding
pads so that the slider bonding pads can be electrically bonded
with respective pads provided on the slider.
18. A head gimbal assembly comprising: a micro-actuator; a slider;
and a suspension that supports the micro-actuator and the slider,
wherein the micro-actuator includes: a bottom support connected to
the suspension by one of welding or epoxy bonding, the bottom
support including suspension bonding pads adapted to be
electrically bonded with respective pads provided on the
suspension; a top support to support the slider; a pair of side
arms that interconnect the bottom support and the top support; a
PZT element mounted to each of the side arms, each PZT element
being excitable to cause selective movement of the side arms which
causes movement of the top support to cause movement of the slider;
and a bonding pad support integrated to and extending from the top
support, the bonding pad support including slider bonding pads that
are electrically bonded with respective pads provided on the
slider, wherein the suspension bonding pads are electrically
connected to the slider bonding pads through a trace that is
integrated to the bottom support, the top support and the bonding
pad support and supported only by the bottom support, the top
support and the bonding pad support.
19. The head gimbal assembly according to claim 18, wherein the
slider includes a read/write element for magnetic recording.
20. The head gimbal assembly according to claim 18, wherein the
bottom support is connected to a suspension tongue of the
suspension.
21. The head gimbal assembly according to claim 18, wherein the
trace includes opposing trace lines having intermediate portions
that curve inwardly towards one another.
22. The head gimbal assembly according to claim 18, wherein the
trace includes opposing trace lines having intermediate portions
that curve outwardly away from one another.
23. The head gimbal assembly according to claim 18, wherein the
trace includes opposing trace lines having end portions that curve
inwardly towards one another.
24. The head gimbal assembly according to claim 18, wherein the
trace includes opposing trace lines that are substantially parallel
with one another.
25. The head gimbal assembly according to claim 18, wherein the
trace is integrated into a front surface of the bottom support, the
top support, and the bonding pad support that faces towards the
slider.
26. The head gimbal assembly according to claim 18, wherein the
trace is integrated into a back surface of the bottom support, the
top support, and the bonding pad support that faces away from the
slider.
27. The head gimbal assembly according to claim 26, wherein the
bonding pad support includes an opening that exposes the slider
bonding pads so that the slider bonding pads can be electrically
bonded with respective pads provided on the slider.
28. The head gimbal assembly according to claim 18, further
comprising an extension integrated to and extending from the bottom
support, the extension including suspension bonding pads adapted to
be electrically bonded with respective pads provided on the
suspension.
29. The head gimbal assembly according to claim 28, wherein the
suspension bonding pads are electrically connected to the slider
bonding pads through a trace that is integrated into the bottom
support, the top support, the bonding pad support, and the
extension.
30. The head gimbal assembly according to claim 29, wherein the
trace includes opposing trace lines having intermediate portions
that curve inwardly towards one another.
31. The head gimbal assembly according to claim 29, wherein the
trace is integrated into a front surface of the bottom support, the
top support, the bonding pad support, and the extension that faces
towards the slider.
32. The head gimbal assembly according to claim 29, wherein the
trace is integrated into a back surface of the bottom support, the
top support, the bonding pad support, and the extension that faces
away from the slider.
33. The head gimbal assembly according to claim 32, wherein the
bonding pad support includes an opening that exposes the slider
bonding pads so that the slider bonding pads can be electrically
bonded with respective pads provided on the slider.
34. A disk drive device comprising: a head gimbal assembly
including a micro-actuator, a slider, and a suspension that
supports the micro-actuator and slider; a drive arm connected to
the head gimbal assembly; a disk; and a spindle motor operable to
spin the disk, wherein the micro-actuator includes: a bottom
support connected to the suspension by one of welding or epoxy
bonding, the bottom support including suspension bonding pads
adapted to be electrically bonded with respective pads provided on
the suspension; a top support to support the slider; a pair of side
arms that interconnect the bottom support and the top support; a
PZT element mounted to each of the side arms, each PZT element
being excitable to cause selective movement of the side arms which
causes movement of the top support to cause movement of the slider;
and a bonding pad support integrated to and extending from the top
support, the bonding pad support including slider bonding pads that
are electrically bonded with respective pads provided on the
slider, wherein the suspension bonding pads are electrically
connected to the slider bonding pads through a trace that is
integrated to the bottom support, the top support and the bonding
pad support and supported only by the bottom support, the top
support and the bonding pad support.
35. A micro-actuator frame for a head gimbal assembly, comprising:
a bottom support adapted to be connected to a suspension of the
head gimbal assembly; a top support adapted to support a slider of
the head gimbal assembly; a pair of side arms that interconnect the
bottom support and the top support; a first set of bonding pads
provided to the bottom support and a second set of bonding pads
provided to the top support; and a trace integrated to the bottom
support and the top support, supported only by the bottom support
and the top support, and laminated between the side arms, the trace
interconnecting the first set of bonding pads and the second set of
bonding pads.
36. The micro-actuator frame according to claim 35, further
comprising a bonding pad support integrated to and extending from
the top support, the bonding pad support supporting the second set
of bonding pads.
37. The micro-actuator frame according to claim 35, wherein the
trace includes opposing trace lines having end portions that curve
inwardly towards one another, the end portions that curve inwardly
towards one another being laminated on the bottom support.
Description
FIELD OF THE INVENTION
The present invention relates to information recording disk drive
devices and, more particularly, to a micro-actuator for a head
gimbal assembly (HGA) of the disk drive device. More specifically,
the present invention is directed to a micro-actuator that is
structured to reduce trace vibrations.
BACKGROUND OF THE INVENTION
One known type of information storage device is a disk drive device
that uses magnetic media to store data and a movable read/write
head that is positioned over the media to selectively read from or
write to the disk.
Consumers are constantly desiring greater storage capacity for such
disk drive devices, as well as faster and more accurate reading and
writing operations. Thus, disk drive manufacturers have continued
to develop higher capacity disk drives by, for example, increasing
the density of the information tracks on the disks by using a
narrower track width and/or a narrower track pitch. However, each
increase in track density requires that the disk drive device have
a corresponding increase in the positional control of the
read/write head in order to enable quick and accurate reading and
writing operations using the higher density disks. As track density
increases, it becomes more and more difficult using known
technology to quickly and accurately position the read/write head
over the desired information tracks on the storage media. Thus,
disk drive manufacturers are constantly seeking ways to improve the
positional control of the read/write head in order to take
advantage of the continual increases in track density.
One approach that has been effectively used by disk drive
manufacturers to improve the positional control of read/write heads
for higher density disks is to employ a secondary actuator, known
as a micro-actuator, that works in conjunction with a primary
actuator to enable quick and accurate positional control for the
read/write head. Disk drives that incorporate a micro-actuator are
known as dual-stage actuator systems.
Various dual-stage actuator systems have been developed in the past
for the purpose of increasing the access speed and fine tuning the
position of the read/write head over the desired tracks on high
density storage media. Such dual-stage actuator systems typically
include a primary voice-coil motor (VCM) actuator and a secondary
micro-actuator, such as a PZT element micro-actuator. The VCM
actuator is controlled by a servo control system that rotates the
actuator arm that supports the read/write head to position the
read/write head over the desired information track on the storage
media. The PZT element micro-actuator is used in conjunction with
the VCM actuator for the purpose of increasing the positioning
access speed and fine tuning the exact position of the read/write
head over the desired track. Thus, the VCM actuator makes larger
adjustments to the position of the read/write head, while the PZT
element micro-actuator makes smaller adjustments that fine tune the
position of the read/write head relative to the storage media. In
conjunction, the VCM actuator and the PZT element micro-actuator
enable information to be efficiently and accurately written to and
read from high density storage media.
One known type of micro-actuator incorporates PZT elements for
causing fine positional adjustments of the read/write head. Such
PZT micro-actuators include associated electronics that are
operable to excite the PZT elements on the micro-actuator to
selectively cause expansion or contraction thereof. The PZT
micro-actuator is configured such that expansion or contraction of
the PZT elements causes movement of the micro-actuator which, in
turn, causes movement of the read/write head. This movement is used
to make faster and finer adjustments to the position of the
read/write head, as compared to a disk drive unit that uses only a
VCM actuator. Exemplary PZT micro-actuators are disclosed in, for
example, JP 2002-133803, entitled "Micro-actuator and HGA" and JP
2002-074871, entitled "Head Gimbal Assembly Equipped with Actuator
for Fine Position, Disk Drive Equipped with Head Gimbals Assembly,
and Manufacture Method for Head Gimbal Assembly."
FIG. 1 illustrates a conventional disk drive unit and show a
magnetic disk 101 mounted on a spindle motor 102 for spinning the
disk 101. A voice coil motor arm 104 carries a head gimbal assembly
(HGA) 100 that includes a micro-actuator 105 with a slider 103
incorporating a read/write head. A voice-coil motor (VCM) is
provided for controlling the motion of the motor arm 104 and, in
turn, controlling the slider 103 to move from track to track across
the surface of the disk 101, thereby enabling the read/write head
to read data from or write data to the disk 101. In operation, a
lift force is generated by the aerodynamic interaction between the
slider 103, incorporating the read/write transducer, and the
spinning magnetic disk 101. The lift force is opposed by equal and
opposite spring forces applied by a suspension of the HGA 100 such
that a predetermined flying height above the surface of the
spinning disk 101 is maintained over a full radial stroke of the
motor arm 104.
FIG. 2 illustrates the head gimbal assembly (HGA) 100 of the
conventional disk drive device of FIG. 1 incorporating a dual-stage
actuator. However, because of the inherent tolerances of the VCM
and the head suspension assembly, the slider 103 cannot achieve
quick and fine position control which adversely impacts the ability
of the read/write head to accurately read data from and write data
to the disk. As a result, a PZT micro-actuator 105, as described
above, is provided in order to improve the positional control of
the slider and the read/write head. More particularly, the PZT
micro-actuator 105 corrects the displacement of the slider 103 on a
much smaller scale, as compared to the VCM, in order to compensate
for the resonance tolerance of the VCM and/or head suspension
assembly. The micro-actuator 105 enables, for example, the use of a
smaller recording track pitch, and can increase the
"tracks-per-inch" (TPI) value by 50% for the disk drive unit, as
well as provide an advantageous reduction in the head seeking and
settling time. Thus, the PZT micro-actuator 105 enables the disk
drive device to have a significant increase in the surface
recording density of the information storage disks used
therein.
As shown in FIG. 2, the HGA 100 includes a suspension 106 having a
flexure 108. The flexure 108 provides a suspension tongue 110 to
load the PZT micro-actuator 105 and the slider 103. Two outwardly
protruding traces 112, 114 are provided to the flexure 108 on
opposite sides of the suspension tongue 110. Each of the traces
112, 114 has one end portion connected with a float plate 116 and
another end portion connected with multi traces 118 that are
electrically connected to bonding pads 120.
Referring to FIG. 3, a conventional PZT micro-actuator 105 includes
a metal frame 130 which has a top support 132, a bottom support
134, and two side arms 136, 138 that interconnect the two supports
132 and 134. The side arms 136, 138 each have a PZT element 140,
142 attached thereto. The slider 103 is supported on the top
support 132.
Referring to FIG. 4, the PZT micro-actuator 105 is physically
coupled to the suspension tongue 110 by the bottom support 134 of
the frame 130. The bottom support 134 may be mounted on the
suspension tongue 110 by epoxy or laser welding, for example. Three
electrical connection balls 150 (gold ball bonding or solder ball
bonding, GBB or SBB) are provided to couple the PZT micro-actuator
105 to the suspension traces 118 located at the side of each PZT
element 140, 142. In addition, there are four metal balls 152 (GBB
or SBB) for coupling the slider 103 to the traces 118 for
electrical connection of the read/write transducers. When power is
supplied through the suspension traces 118, the PZT elements 140,
142 expand or contract to cause the two side arms 136, 138 to bend
in a common lateral direction. The bending causes a shear
deformation of the frame 130, e.g., the rectangular shape of the
frame becomes approximately a parallelogram, which causes movement
of the top support 132. This causes movement of the slider 103
connected thereto, thereby making the slider 103 move on the track
of the disk in order to fine tune the position of the read/write
head. In this manner, controlled displacement of slider 103 can be
achieved for fine positional tuning.
FIG. 5 illustrates how the PZT micro-actuator 105 works when a
voltage is applied to the PZT elements 140, 142. For example, when
a positive sine voltage is input to the PZT element 140 of the
micro-actuator which has a positive polarization, in the first half
period, the PZT element 140 will shrink and cause the side arm 136
to deform as a water waveform shape. Since the slider 103 is
mounted on the top support 132, this deformation will cause the
slider to move towards the left side. Likewise, when a negative
sine voltage is input to the PZT element 142 of the micro-actuator
which has a positive polarization, in the second half period, the
PZT element 142 will shrink and cause the side arm 138 to deform as
a water waveform shape. This deformation will cause the slider 103
to move towards the right side. Of course, this operation may
depend on the electric control circle and PZT element polarization
direction, but the work principle is well known.
Referring to FIG. 6, two outwardly protruding traces 112, 114 have
to be used to electrically connect the multi-traces 118 with the
float plate 116 which is electrically connected with the slider
103. In order to reduce the trace resistance due to stiffness of
the trace and maintain the micro-actuator function during
operation, the traces 112, 114 are shaped so as to curve and extend
on opposite sides of the suspension tongue 110. This arrangement
allows the traces 112, 114 to vibrate and move when the
micro-actuator is operated during head seeking or settling
operations in the disk drive device, which will cause the slider to
be off-track. For a high RPM multi-plate disk drive device, the
outwardly curved traces 112, 114 will also cause a windage problem
as air flow hits the traces or suspension. Both of these issues
will cause slider PES (positional error signal ) and NRRO
(non-repeatable runout) performance to worsen, which will limit the
capacity and performance of the disk drive device.
For example, FIG. 6 illustrates the motion of the traces 112, 114
when the micro-actuator 105 is operated. As illustrated, when a
voltage is input to the micro-actuator 105, movement of the side
arms 136, 138 may cause the trace 112 to sway to the back side of
the suspension 106 and the other trace 114 to sway to the top side
of the slider 103. This kind of motion will cause a suspension
resonance motion, which is one of the sources that causes the
slider to be off-track.
FIG. 7 illustrates trace motion displacement results for a prior
art design when the micro-actuator is operated. As discussed above,
the prior art design includes outwardly protruding traces 112, 114.
The displacement of the traces is measured against the frequency.
As illustrated, the displacement trend includes three peaks 160
(e.g., at 4 Khz, 6.3 kHz, and 8.5 Khz ).
FIG. 8 illustrates related measurement data of the slider head NRRO
performance for a prior art design. As illustrated, the peaks 170
show a slider head off track percentage with a different frequency.
This shows a relatively large off track due to the trace
motion.
Thus, there is a need for an improved system that does not suffer
from the above-mentioned drawbacks.
SUMMARY OF THE INVENTION
One aspect of the present invention relates to a micro-actuator
structured to reduce trace vibrations.
Another aspect of the invention relates to a micro-actuator having
a frame with an integrated trace and bonding pad support.
Another aspect of the invention relates to a micro-actuator for a
head gimbal assembly. The micro-actuator includes a frame, a first
set of bonding pads provided to one end of the frame, a second set
of bonding pads provided to an opposing end of the frame, and a
trace integrated to the frame. The trace interconnects the first
set of bonding pads and the second set of bonding pads.
Another aspect of the invention relates to a micro-actuator for a
head gimbal assembly. The micro-actuator includes a bottom support
adapted to be connected to a suspension of the head gimbal
assembly, a top support adapted to support a slider of the head
gimbal assembly, a pair of side arms that interconnect the bottom
support and the top support, and a PZT element mounted to each of
the side arms. Each PZT element is excitable to cause selective
movement of the side arms which causes movement of the top support
to cause movement of the slider. A bonding pad support is
integrated to and extends from the top support. The bonding pad
support includes slider bonding pads adapted to be electrically
bonded with respective pads provided on the slider.
Yet another aspect of the invention relates to a head gimbal
assembly including a micro-actuator, a slider, and a suspension
that supports the micro-actuator and the slider. The micro-actuator
includes a bottom support connected to the suspension by one of
welding or epoxy bonding, a top support to support the slider, a
pair of side arms that interconnect the bottom support and the top
support, and a PZT element mounted to each of the side arms. Each
PZT element is excitable to cause selective movement of the side
arms which causes movement of the top support to cause movement of
the slider. A bonding pad support is integrated to and extends from
the top support. The bonding pad support includes slider bonding
pads that are electrically bonded with respective pads provided on
the slider.
Yet another aspect of the invention relates to a disk drive device.
The disk drive device includes a head gimbal assembly including a
micro-actuator, a slider, and a suspension that supports the
micro-actuator and slider; a drive arm connected to the head gimbal
assembly; a disk; and a spindle motor operable to spin the disk.
The micro-actuator includes a bottom support connected to the
suspension by one of welding or epoxy bonding, a top support to
support the slider, a pair of side arms that interconnect the
bottom support and the top support, and a PZT element mounted to
each of the side arms. Each PZT element is excitable to cause
selective movement of the side arms which causes movement of the
top support to cause movement of the slider. A bonding pad support
is integrated to and extends from the top support. The bonding pad
support includes slider bonding pads that are electrically bonded
with respective pads provided on the slider.
Still another aspect of the invention relates to a micro-actuator
frame for a head gimbal assembly. The micro-actuator frame includes
a bottom support adapted to be connected to a suspension of the
head gimbal assembly, a top support adapted to support a slider of
the head gimbal assembly, a pair of side arms that interconnect the
bottom support and the top support, a first set of bonding pads
provided to the bottom support and a second set of bonding pads
provided to the top support, and a trace integrated to the frame
and laminated between the side arms. The trace interconnects the
first set of bonding pads and the second set of bonding pads.
Other aspects, features, and advantages of this invention will
become apparent from the following detailed description when taken
in conjunction with the accompanying drawings, which are a part of
this disclosure and which illustrate, by way of example, principles
of this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings facilitate an understanding of the
various embodiments of this invention. In such drawings:
FIG. 1 is a perspective view of a conventional disk drive unit;
FIG. 2 is a perspective view of a conventional head gimbal assembly
(HGA);
FIG. 3 is a perspective view of a slider and PZT micro-actuator of
the HGA shown in FIG. 2;
FIG. 4 is a partial perspective view of the HGA shown in FIG.
2;
FIG. 5 is a top view of the slider and PZT micro-actuator of the
HGA shown in FIG. 2 in use;
FIG. 6 is a partial perspective view of the HGA shown in FIG. 2 in
use;
FIG. 7 shows trace motion displacement results for a prior art
design;
FIG. 8 shows slider head NRRO performance for a prior art
design;
FIG. 9 is a perspective view of a head gimbal assembly (HGA)
including a PZT micro-actuator according to an embodiment of the
present invention;
FIG. 10 is a partial perspective of the HGA shown in FIG. 9;
FIG. 11 is an exploded view of the HGA shown in FIG. 10;
FIG. 12 is a side view of the HGA shown in FIG. 10;
FIG. 13 shows trace motion displacement results for the HGA shown
in FIG. 9;
FIG. 14 shows slider head NRRO performance for the HGA shown in
FIG. 9;
FIG. 15 is a perspective view of a slider and a PZT micro-actuator
according to another embodiment of the present invention;
FIG. 16 is a perspective view of a slider and a PZT micro-actuator
according to another embodiment of the present invention;
FIG. 17 is a perspective view of a slider and a PZT micro-actuator
according to another embodiment of the present invention;
FIG. 18 is an exploded view of a head gimbal assembly (HGA)
including a PZT micro-actuator according to another embodiment of
the present invention;
FIG. 19 is a perspective view of a slider and a PZT micro-actuator
according to yet another embodiment of the present invention;
FIG. 20 is a perspective view of the slider and a PZT
micro-actuator shown in FIG. 19 mounted to the suspension of a HGA;
and
FIG. 21 is a perspective view of a slider and a PZT micro-actuator
according to still another embodiment of the present invention.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS
Various preferred embodiments of the instant invention will now be
described with reference to the figures, wherein like reference
numerals designate similar parts throughout the various views. As
indicated above, the instant invention is designed to reduce trace
vibrations in a head gimbal assembly (HGA) while precisely
actuating the slider using the micro-actuator. An aspect of the
instant invention is to provide a micro-actuator that includes an
integrated trace and bonding pad support configured to reduce trace
vibrations in the HGA. By reducing the trace vibrations in the HGA,
the performance characteristics of the device are improved.
Several example embodiments of a micro-actuator for a HGA will now
be described. It is noted that the micro-actuator may be
implemented in any suitable disk drive device having a
micro-actuator in which it is desired to reduce trace vibrations,
regardless of the specific structure of the HGA as illustrated in
the figures. That is, the invention may be used in any suitable
device having a micro-actuator in any industry.
FIGS. 9-12 illustrates a head gimbal assembly (HGA) 210
incorporating a PZT micro-actuator 212 according to a first
exemplary embodiment of the present invention. The HGA 210 includes
a PZT micro-actuator 212, a slider 214, and a suspension 216 to
load or suspend the PZT micro-actuator 212 and the slider 214.
As illustrated, the suspension 216 includes a base plate 218, a
load beam 220, a hinge 222, a flexure 224, and inner and outer
suspension traces 226, 227 in the flexure 224. The base plate 218
includes a mounting hole 228 for use in connecting the suspension
216 to a drive arm of a voice coil motor (VCM) of a disk drive
device. The shape of the base plate 218 may vary depending on the
configuration or model of the disk drive device. Also, the base
plate 218 is constructed of a relatively hard or rigid material,
e.g., metal, to stably support the suspension 216 on the drive arm
of the VCM.
The hinge 222 is mounted onto the base plate 218 and load beam 220,
e.g., by welding. As illustrated, the hinge 222 includes a hole 230
that align with the hole 228 provided in the base plate 218. Also,
the hinge 222 includes a holder bar 232 for supporting the load
beam 220.
The load beam 220 is mounted onto the holder bar 232 of the hinge
222, e.g., by welding. The load beam 220 has a dimple 234 formed
thereon for engaging the flexure 224 (see FIG. 12). The load beam
220 functions as a spring or shock absorber to buffer the
suspension 216 from the slider 214. An optional lift tab 236 may be
provided on the load beam 220 to lift the HGA 210 from the disk
when the disk is not rotated.
The flexure 224 is mounted to the hinge 222 and the load beam 220,
e.g., by lamination or welding. The flexure 224 provides a
suspension tongue 238 to couple the PZT micro-actuator 212 to the
suspension 216 (see FIG. 11). The suspension tongue 238 engages the
dimple 234 on the load beam 220. Also, the suspension traces 226,
227 are provided on the flexure 224 to electrically connect a
plurality of connection pads 240 (which connect to an external
control system) with the slider 214 and the PZT elements 242 on the
PZT micro-actuator 212. The suspension traces 226, 227 may be a
flexible printed circuit (FPC) and may include any suitable number
of lines.
As best shown in FIGS. 10 and 11, bonding pads 244 are directly
connected to the inner suspension traces 226 to electrically
connect the inner suspension traces 226 with bonding pads 246
provided on the frame of the PZT micro-actuator 212, which is
electrically connected to the slider 214. Also, bonding pads 248
are directly connected to the outer suspension traces 227 to
electrically connect the outer suspension traces 227 with bonding
pads 250 provided on the PZT elements 242.
A voice-coil motor (VCM) is provided in the disk drive device for
controllably driving the drive arm and, in turn, the HGA 210 in
order to enable the HGA 210 to position the slider 214, and
associated read/write head, over any desired information track on a
disk in the disk drive device. The PZT micro-actuator 212 is
provided to enable faster and finer positional control for the
device, as well as to reduce the head seeking and settling time
during operation. Thus, when the HGA 210 is incorporated into a
disk drive device, a dual-stage actuator system is provided in
which the VCM actuator provides large positional adjustments and
the PZT micro-actuator 212 provides fine positional adjustments for
the read/write head.
FIG. 11 illustrates the PZT micro-actuator 212 and slider 214
removed from the suspension 216. As illustrated, the PZT
micro-actuator 212 includes a micro-actuator frame 252 and PZT
elements 242 mounted to the micro-actuator frame 252. The
micro-actuator frame 252 includes a top support 254, a bottom
support 256, side arms 258 that interconnect the top support 254
and bottom support 256, and a bonding pad support 260 that extends
from the top support 254. The micro-actuator frame 252 may be
constructed of any suitable material, e.g., metal, and may be
constructed using any suitable process.
As best shown in FIG. 10, the bottom support 256 is structured to
connect the micro-actuator frame 252 to the suspension 216.
Specifically, the bottom support 256 is partially mounted to the
suspension tongue 238 of the flexure 224, e.g., by epoxy, resin, or
welding by laser. Also, suspension bonding pads 246, e.g., four
bonding pads, are provided on the bottom support 256. The
suspension bonding pads 246 are electrically coupled by electric
connections 262 with respective bonding pads 244 provided on the
suspension 216, e.g., by wire bonding. This connects the bottom
support 256 to the suspension 216 and electrically connects the
micro-actuator frame 252 with the inner suspension traces 226.
Also, a parallel gap 280 is provided between the suspension tongue
238 and the PZT micro-actuator 212 to allow the PZT micro-actuator
212 to move freely in use, as shown in FIG. 12.
The top support 254 is structured to connect the micro-actuator
frame 252 to the slider 214. Specifically, slider bonding pads 264,
e.g., four bonding pads, are provided on the bonding pad support
260 extending from the top support 254. As shown in FIG. 11, the
slider bonding pads 264 are electrically connected to the
suspension bonding pads 246 through traces 266 integrated into the
frame 252. The slider 214 has bonding pads 268, e.g., four bonding
pads, on an end thereof corresponding to the slider bonding pads
264 of the bonding pad support 260. The top support 254 supports
the slider 214 thereon and the slider bonding pads 264 of the
bonding pad support 260 are electrically bonded with respective
pads 268 provided on the slider 214 using, for example, electric
connection balls (GBB or SBB) 270 (see FIGS. 10 and 12). This
connects the top support 254 to the slider 214 and electrically
connects the slider 214 and its read/write elements to the inner
suspension traces 226 on the suspension 216.
In the illustrated embodiment, the trace 266 includes four lines
between the four slider bonding pads 264 and the four suspension
bonding pads 246. However, any suitable number of pads and trace
lines may be used. Also, as best shown in FIG. 11, intermediate
portions 272 of opposing trace lines curve inwardly towards one
another. However, the trace lines may have any suitable
configuration.
The side arms 258 interconnect the top support 254 and the bottom
support 256. A PZT element 242 is mounted to each of the side arms
258 of the nicro-actuator frame 252 to provide the PZT
micro-actuator 112. Each PZT element 242 has a plate-like shape and
may be formed by laminated thin films consisting of piezoelectric
material such as PZT and Ni--Ag or Pt or gold metal as electrode.
In another embodiment, the PZT element 242 may be a ceramic PZT
with a single layer or a multi-layer. However, one or more PZT
elements 242 may be mounted to the side arms 258 in any suitable
manner.
A slider 214 is mounted to the PZT micro-actuator 212 to provide a
slider and PZT micro-actuator assembly 274. The slider 214 is
mounted to the PZT micro-actuator 212 as shown in FIG. 10. As
explained above, the slider 214, incorporating the read/write head,
is electrically bonded to the slider bonding pads 264 of the
micro-actuator frame 252 by electrical connection balls (GBB or
SBB) 270.
The slider and PZT micro-actuator assembly 274 is electrically
connected to the suspension 216 of the HGA 210. As explained above,
electrical connections 262 are provided to electrically connect the
suspension bonding pads 246 on the bottom support 256 of the
micro-actuator frame 252 to the bonding pads 244 bonded to the
inner suspension traces 226 provided on the suspension 216. In
addition, the PZT elements 242 provided on the PZT micro-actuator
212 are electrically connected to the outer suspension traces 227.
Specifically, the bonding pads 250, e.g., two bonding pads,
provided on the PZT elements 242 are electrically connected to the
bonding pads 248, e.g., two bonding pads, on the outer suspension
traces 227 using electrical connection balls (GBB or SBB) 276. This
allows power to be applied via the outer suspension traces 227 to
the PZT elements 242.
In use, the PZT elements 242 are excited, e.g., by applying voltage
thereto, to selectively cause expansion or contraction thereof. The
PZT micro-actuator 212 is configured such that expansion or
contraction of the PZT elements 242 causes movement of the side
arms 258, which causes movement of the top support 254, which, in
turn, causes movement of the slider 214 coupled thereto.
Because the trace 266 and the bonding pad support 260 are
integrated into the micro-actuator frame 252, these components are
not subject to excessive vibration when the PZT micro-actuator 212
is operated. By reducing the trace vibrations in the HGA, the
performance characteristics of the disk drive device are improved.
Moreover, PZT micro-actuator 212 with integrated trace 266 and
bonding pad support 260 improves the process yield as these
components are not easily deformed during the manufacture of the
suspension, HGA, and disk drive device.
FIG. 13 illustrates trace motion displacement results when the PZT
micro-actuator 212 is operated. When compared to the results of the
prior art design in FIG. 7, the three peaks 284 of FIG. 13 are
improved with respect to the three peaks 160 of FIG. 7 (e.g., at 4
Khz, 6.3 kHz, and 8.5 Khz ).
FIG. 14 illustrates testing data of slider head NRRO performance
for the PZT micro-actuator 212. When compared to the results of the
prior art design in FIG. 8, the peaks 286 of FIG. 14 are improved
with respect to the peaks 170 of FIG. 8.
As noted above, the trace lines interconnecting the slider bonding
pads 264 and the suspension bonding pads 246 may have any suitable
configuration. For example, FIG. 15 illustrates a PZT
micro-actuator 312 according to another exemplary embodiment of the
present invention. In this embodiment, intermediate portions 372 of
opposing trace lines of the traces 366 curve outwardly away from
one another. The remaining components of the PZT micro-actuator 312
are substantially similar to the PZT micro-actuator 212 and
indicated with similar reference numerals.
FIG. 16 illustrates a PZT micro-actuator 412 according to another
exemplary embodiment of the present invention. In this embodiment,
end portions 472 of opposing trace lines of the traces 466 curve
inwardly towards one another. The remaining components of the PZT
micro-actuator 412 are substantially similar to the PZT
micro-actuator 212 and indicated with similar reference
numerals.
FIG. 17 illustrates a PZT micro-actuator 512 according to another
exemplary embodiment of the present invention. In this embodiment,
opposing trace lines of the traces 566 are substantially parallel
with one another. The remaining components of the PZT
micro-actuator 512 are substantially similar to the PZT
micro-actuator 212 and indicated with similar reference
numerals.
FIG. 18 illustrates a PZT micro-actuator 612 according to another
exemplary embodiment of the present invention. In this embodiment,
the traces 666 are provided on the back side of the frame 652. The
traces 666 may have any suitable configuration as described above.
As illustrated, an opening or window 690 is provided in the bonding
pad support 660 in order to expose the slider bonding pads 264 for
bonding with the slider 214. Also, ACF 692 or other suitable
material may be used to physically and electrically couple the
suspension bonding pads 246 to the pads 244 provided on the
suspension 216. The remaining components of the PZT micro-actuator
612 are substantially similar to the PZT micro-actuator 212 and
indicated with similar reference numerals.
FIGS. 19 and 20 illustrates a PZT micro-actuator 712 according to
yet another exemplary embodiment of the present invention. In this
embodiment, the bottom support 256 of the frame 252 may include an
extension 794, e.g., long tail leader, to facilitate connection
with the suspension 216. For example, the bottom support 256 may be
physically mounted to the suspension tongue 238 of the suspension
216, e.g., by laser welding or epoxy. The extension 794, including
the suspension bonding pads 246, may be electrically coupled to the
pads 244 provided on the suspension 216, e.g., by US bonding. The
remaining components of the PZT micro-actuator 712 are
substantially similar to the PZT micro-actuator 212 and indicated
with similar reference numerals.
FIG. 21 illustrate a PZT micro-actuator 812 according to still
another exemplary embodiment of the present invention. In this
embodiment, the bottom support 256 of the frame 252 may include an
extension 894, e.g., long tail leader, to facilitate connection
with the suspension 216 as described above. Further, the traces 866
interconnecting the slider bonding pads 264 and the suspension
bonding pads 246 are provided on the back side of the frame 852.
The traces 866 may have any suitable configuration as described
above. As illustrated, an opening 890 is provided in the bonding
pad support 860 in order to expose the slider bonding pads 264 for
bonding with the slider 214. The remaining components of the PZT
micro-actuator 812 are substantially similar to the PZT
micro-actuator 212 and indicated with similar reference
numerals.
A head gimbal assembly 210 incorporating a PZT micro-actuator 212,
312, 412, 512, 612, 712, 812 according to embodiments of the
present invention may be provided to a disk drive device (HDD). The
HDD may be of the type described above in connection with FIG. 1.
Because the structure, operation and assembly processes of disk
drive devices are well known to persons of ordinary skill in the
art, further details regarding the disk drive device are not
provided herein so as not to obscure the invention. The PZT
micro-actuator can be implemented in any suitable disk drive device
having a micro-actuator or any other device with a micro-actuator.
In an embodiment, the PZT micro-actuator is used in a high RPM disk
drive device.
While the invention has been described in connection with what are
presently considered to be the most practical and preferred
embodiments, it is to be understood that the invention is not to be
limited to the disclosed embodiments, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the invention.
* * * * *